EHS 2025 Poster: Spinal deformity and spinal stiffness are related to each other
Koki Abe, Sarah Kenny, Bill Walter, Henry Bian
Understanding Spinopelvic Mobility in THA
Spinopelvic analysis plays an important role in preoperative planning for total hip arthroplasty (THA), helping to identify patients at higher risk of post-operative complications. In a study of 270 elective THA patients assessed with the Navbit Rapid Surgical Plan®, three measures of spinopelvic mobility—PI-LL alignment, sacral slope change (ΔSS), and lumbar flexion—were compared. Each patient’s spinal condition was also categorised as normal, mild, moderate, or severe to explore the link between mobility and deformity.
Findings on Stiffness and Spinal Disease
The study found that ΔSS classified more patients as having stiff spines (26%) compared to lumbar flexion (11%), though it may overpredict stiffness. Patients with lumbar flexion stiffness were shown to be 10.8 times more likely to have severe spinal disease, with stiffness strongly linked to underlying deformity. These results suggest that using multiple measures provides a more accurate picture of spinopelvic mobility, ensuring surgeons can make better-informed decisions during THA planning.